1. Field of the Invention
The present invention relates to a data transmission method and the transmission circuit thereof. More particularly, the present invention relates to a data transmission method and the transmission circuit thereof for transmitting a clock signal and a data signal simultaneously.
2. Description of Related Art
Conventional data transmission is generally classified into parallel transmission and serial transmission. When data are transmitted through parallel transmission, more transmission pins are required between chips, and accordingly the cost of the circuit design is higher. Moreover, encoding/decoding circuits are required in parallel transmission for encoding and decoding data, so that larger circuit space is required in circuit design and electromagnetic interference may be easily caused.
Presently serial transmission is mainly accomplished by universal serial bus (USB). Differential signal transmission method is adopted by USB and additional circuit spaces are required at both the sender and the receiver for disposing relative encoding/decoding circuits, thus, data cannot be directly transmitted through software protocol. As to those hand-held electronic devices which are being designed smaller and smaller, such as PDA, intellectual cell phone, GPS, player, and game machine, etc., the disposition of additional circuit or transmission pins will increase the manufacturing cost and complexity in design.